1969] 
Shear — Cave Millipeds 
139 
Causey, Fig. 6) and adjacent western Virginia. A single Kentucky 
record is questionable. Zygonopus seems more distinct from Tricho- 
petalum than is Scoterpes , and the two genera probably had inde- 
pendent origins. Despite a recent revision by Causey (1960a), the 
status of the four described species remains uncertain: “. . . the 
four species I formerly assigned to it \Zygonopus\ . . . are two spe- 
cies, of which one is composed of three subspecies (Causey, 1963b).” 
Family Caseyidae Verhoeff 
This family is poorly known, but probably has many species in 
the Pacific Northwest and California. Causey (1963a) has done 
much to clarify the anatomy of the gonopods. The relationship of 
this family to the small, eastern Family Underwoodiidae needs study. 
Genus Speoseya Causey 
Speoseya grahami Causey, the only known species of this genus, is 
about 10 mm long and is known from caves in Calaveras Co., Cali- 
fornia (Causey, 1963a). 
Genus Opiona Chamberlin 
Opiona siliquae Causey (1963a), from Fault Rock Cave, Men- 
docino Co., California, is about the same size as Speoseya grahami , 
but has ocelli. Two additional epigean species of this genus are 
known from Washington and British Columbia (Chamberlin and 
Hoffman, 1958). 
Family Cleidogonidae Cook 
This is a very large family, distinguished by its large, well-defined 
genera and relatively wide range (from Ontario to Guatemala). 
Members of the genus Cleidogona are sometimes found in the Ap- 
palachian region as accidentals or troglophiles, 3 and will key out as 
caseyids in my artificial key, but the two groups are not sympatric — 
no caseyids occur in the eastern United States. 
Genus Pseudotremia Cope 
Map 3; Fig. 10, 11, 13 
Dearolfia Loomis ( 1939) is a synonym of this genus. Pseudotremia 
is the most widespread and abundant genus of American cave milli- 
peds, and has troglobitic, troglophilic and epigean members. Exam- 
ination of several large collections and of all type material, including 
There are numerous undescribed troglobitic Cleidogona spp. in Mexico. 
